Method of manufacturing a disk drive suspension

ABSTRACT

A method of manufacturing a suspension for a disk drive includes providing and assembling an actuator coupling plate, a bend region, a load beam, and a head receiving gimbal. The load beam has a first end and a second end and defines a longitudinal axis that bisects the first end and the second end. The load beam is coupled to the gimbal proximate the first end and includes a base region proximate the second end, the base region having a first lateral section to one side of the longitudinal axis and a second lateral section to another side of the longitudinal axis. The first and the second lateral sections define a gap therebetween, and the base region has a bridge extending across the gap. A constraint layer overlays the gap and the bridge.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/199,757, filed on Aug. 27, 2008, now U.S. Pat. No. 8,159,785, whichis hereby incorporated by reference in its entirety.

BACKGROUND

Disk drives typically include at least one disk (such as a magnetic,magneto-optical, or optical disk), a spindle motor for rotating thedisk, and a head stack assembly (“HSA”). The HSA may include at leastone head mounted on a suspension for writing data to and reading datafrom the disk. The head is typically driven at high velocities acrossthe disk by a voice coil motor (“VCM”) to provide access to differentlocations.

Suspension dynamics play an important role in the performance of a diskdrive as the head is moved back and forth across the disk. When thesuspension becomes excited at a resonant frequency, the time required tosettle on a desired track can be dramatically increased, and disk driveperformance impacted. Moreover, in some cases, excitation of the diskdrive suspension may result in off-track write errors or even contactbetween the head and the disk. Among the resonances of the disk drivesuspension, the torsion and sway modes are typically the most critical.

In order to improve suspension dynamics and servo bandwidth, many diskdrive suspensions now incorporate a damper. However, the effectivenessof dampers on typical suspensions depends heavily on the strain energyof those areas to which the dampers are attached. That is, applying adamper to a relatively stiff disk drive suspension often yields onlymodest improvements in disk drive suspension dynamics.

There is therefore a need for a disk drive suspension with improveddynamics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view generally illustrating a diskdrive that may incorporate an embodiment.

FIG. 2 is a top, perspective view illustrating an exemplary disk drivesuspension, according to one illustrated embodiment.

FIG. 3 is a bottom, perspective view illustrating the suspension of FIG.2, according to one illustrated embodiment.

FIG. 4 is an exploded, perspective view of a load beam, adhesive layersand constraint layer of the disk drive suspension of FIG. 2, accordingto one illustrated embodiment.

FIG. 5 is a perspective view of the load beam of FIG. 4, according toone illustrated embodiment.

FIG. 6 is a top view of the load beam of FIG. 4, according to oneillustrated embodiment.

FIG. 7 is a side view of the load beam of FIG. 4, according to oneillustrated embodiment.

FIG. 8 is a top view of the constraint layer of FIG. 4, according to oneillustrated embodiment.

FIG. 9 illustrates a flow chart for a method of manufacturing asuspension for a disk drive, according to one illustrated embodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, a disk drive 100 is illustrated, which mayincorporate one or more embodiments of the disk drive suspensiondescribed in greater detail below. As illustrated, the disk drive 100comprises a magnetic disk drive, and the structures and methodsdescribed herein will be described in terms of such a disk drive.However, the structures and methods described herein may also be appliedto and/or implemented in other disk drives, including, e.g., optical andmagneto-optical disk drives.

The disk drive 100 comprises a head disk assembly (“HDA”) 102 and aprinted circuit board (“PCB”) 104. The HDA 102 includes a disk drivebase 106 and a cover 108, which together house a number of disk drivecomponents.

The disk drive 100 further includes a disk 110, which may comprise anyof a variety of magnetic or optical disk media. In one embodiment, thedisk 110 comprises a plurality of generally concentric tracks forstoring data. In other embodiments, more disks 110 may be included inthe disk drive 100.

As illustrated, a motor 112 is coupled to and configured to rotate thedisk 110 about a disk axis of rotation 114. The motor 112 may include amotor hub 116 that is rotatably attached to the disk drive base 106.

The HDA 102 further includes a head stack assembly (“HSA”) 118 rotatablyattached to the disk drive base 106. The HSA 118 may include an actuator120 having one or more actuator arms 122. A head gimbal assembly (“HGA”)124 may be attached to a distal end of each actuator arm 122. Duringoperation, the actuator 120 may be rotated to position the HGA 124adjacent a desired track on the disk 110. In order to accomplish thispositioning, the HSA 118 may include a coil 126 through which a changingelectrical current is passed. The coil 126 interacts with one or moremagnets 128 to form a voice coil motor (“VCM”) for controllably rotatingthe HSA 118.

Each HGA 124 includes a head for writing data to and reading data fromthe disk 110. The head may be adhered to a disk drive suspension thatincludes a gimbal, a load beam, a bend region and a swage plate. In someembodiments, a disk drive suspension like that described in detail belowwith respect to FIGS. 2-8 may be incorporated into the disk drive 100.

The PCB 104 may comprise any of a variety of circuit boards to whichintegrated circuits 130 may be coupled. The integrated circuits 130 mayembody different logical subsystems used to control disk driveoperations. For example, the integrated circuits 130 may include, interalia, a disk drive controller for controlling read and write operationsand a servo control system for generating servo control signals toposition the HGAs 124 relative to the disk 110.

FIGS. 2 and 3 show top and bottom perspective views of an exemplarysuspension 200 for a disk drive, according to one illustratedembodiment. As illustrated, the suspension 200 includes a gimbal 202configured to receive a head 204, a load beam 206 and a constraint layer208. The load beam 206 has a first end 210 and a second end 212 anddefines a longitudinal axis between the first end 210 and the second end212. The load beam 206 is coupled to the gimbal 202 proximate the firstend 210 and includes a base region 214 proximate the second end 212. Asillustrated, the constraint layer 208 overlays at least a portion of thebase region 214. The configuration and geometry of the load beam 206 andthe base region 214 are discussed in greater detail below with respectto FIGS. 4-8.

The gimbal 202 may comprise any of a variety of structures configured toreceive the head 204. In one embodiment, the head 204 may be adhered tothe gimbal 202. In other embodiments, other mechanisms for attaching thehead 204 to the gimbal 202 may be used. In some embodiments, the gimbal202 may be adapted to allow the head 204 to pivot about one or more axesto facilitate the reading and writing operations of the head 204.

The head 204 may comprise any of a variety of heads for writing data toand reading data from a disk. In magnetic recording applications, thehead 204 may include an air bearing slider and a magnetic transducerthat includes a writer and a read element. The magnetic transducer'swriter may be of a longitudinal or perpendicular design, and the readelement of the magnetic transducer may be inductive or magnetoresistive.In optical or magneto-optical recording applications, the head 204 mayinclude a mirror and an objective lens for focusing laser light on to anadjacent disk surface.

The load beam 206 may have any of a variety of shapes and sizes.Although illustrated with a particular outline and a particular patternof holes and crossing members, different geometries may be used alongthe length of the load beam 206 in order to improve a variety ofcharacteristics, such as a fly-height of the head 204, or resonancecharacteristics of the suspension 200. In addition, different load beamsmay be incorporated into larger and smaller disk drive form factors, andmay therefore have a variety of sizes.

In one embodiment, the load beam 206 is coupled to the gimbal 202proximate the first end 210 of the load beam 206. As illustrated, thefirst end 210 of the load beam 206 represents a distal end farthest froma disk drive actuator (not shown), while the second end 212 represents aproximal end nearest the disk drive actuator. As used herein, the term“coupled” is a broad term encompassing any manner of physicalengagement. In some embodiments, the load beam 206 need not bephysically attached to the gimbal 202 at the first end 210 but may beotherwise physically engaged with the gimbal 202 proximate the first end210. For example, as illustrated, the gimbal 202 may be physicallyattached to the load beam 206 near a center of the load beam 206 andpositioned such that the head 204 is in physical engagement with andpivots about a feature of the load beam 206 proximate the first end 210.The gimbal 202 may be physically attached to the load beam 206 in avariety of ways, including adhesives, welding, etc.

In one embodiment, the load beam 206 includes a base region 214proximate the second end 212. As illustrated, the base region 214 maydefine the second end 212 of the load beam 206. However, in otherembodiments, the base region 214 may be separated from the second end212 by at least some length of the load beam 206.

The load beam 206 may be formed from any of a variety of materials. Inone embodiment, the load beam 206 is a monolithic, metallic component.For example, the load beam 206 may be etched or stamped from a singlepiece of stainless steel. In other embodiments, other materials andmanufacturing methods may be used.

The constraint layer 208 may overlay at least a portion of the baseregion 214. In one embodiment, the constraint layer 208 acts as adamping layer for the suspension 200, damping vibrations that may arisein the suspension 200 during operation of a disk drive. A variety ofmaterials may be used to form the constraint layer 208. For example, indifferent embodiments, the constraint layer 208 may comprise polyimide,stainless steel, MELINEX® 329 (produced by DuPont) or MYLAR® (alsoproduced by DuPont). In some embodiments, the constraint layer 208 mayitself comprise a plurality of layers of the same or different materialsin order to achieve the desired damping characteristics.

The constraint layer 208 may have any of a variety of geometries. In oneembodiment, the constraint layer 208 may overlay substantially all ofthe base region 214, as illustrated in the Figures. Moreover, theconstraint layer 208 may be substantially congruent with the base region214, as illustrated. Of course, in other embodiments, the constraintlayer 208 may only overlay a portion of the base region 214 and may havea dramatically different shape than that of the base region 214. Theconstraint layer 208 may also have any of a variety of thicknesses. Inone embodiment, the constraint layer 208 may have a thickness of betweenapproximately 1 mil and 6 mil (i.e., between approximately 0.025 mm and0.15 mm). Depending on the material(s) chosen for the constraint layer208, different thicknesses may be optimal. Indeed, in some embodiments,the thickness of the constraint layer 208 may vary over its surfacearea.

The disk drive suspension 200 may further comprise a bend region 216adjacent the second end 212 of the load beam 206. In one embodiment, thebend region 216 may function in part to preload the head 204 in thedirection of a disk surface. The suspension 200 may further comprise aswage plate 218 adjacent the bend region 216. When assembled, the swageplate 218 may be coupled to a distal end of an actuator arm (not shown)by a swaging process.

FIG. 4 is an exploded, perspective view of the load beam 206, adhesivelayers 220 a, b and the constraint layer 208 of the disk drivesuspension 200 of FIG. 2. FIGS. 5-7 show perspective, top and side viewsof the load beam 206, and FIG. 8 illustrates a top view of theconstraint layer 208. The geometry and arrangement of these parts arediscussed in further detail below with reference to these Figures.

As illustrated, the base region 214 of the load beam 206 may have afirst lateral section 222 to one side of a longitudinal axis L (shown inFIG. 6) of the load beam 206 and a second lateral section 224 to anotherside of the longitudinal axis L. The first and second lateral sections222, 224 define a gap G therebetween. In one embodiment, the base region214 has a bridge section 226 extending across the gap G between thefirst lateral section 222 and the second lateral section 224.

As shown in FIG. 6, the gap G may be defined between a first edge 228 ofthe first lateral section 222 and a second edge 230 of the secondlateral section 224, the second edge 230 opposite the first edge 228.The gap G may have any of a variety of widths. In one embodiment, thegap G may have a width GW (as illustrated in FIG. 6) of less thanapproximately 0.4 mm. In another embodiment, the gap G may have a widthGW of between approximately 0.05 mm and 0.4 mm. In one embodiment, thewidth GW may be chosen based at least in part upon a desired resonantfrequency for the load beam 206, as well as upon a desired elasticstrain energy at the base region 214. In other embodiments, more complexcontours of the first and second lateral sections 222, 224 may definethe gap G, and the gap G may have a varying width along the longitudinalaxis L.

In the illustrated embodiment, the gap G is substantially aligned withthe longitudinal axis L of the load beam 206. However, in otherembodiments, the gap G may be off-center with respect to thelongitudinal axis L.

The gap G may also be divided into two or more portions by one or morebridge sections. As best seen in FIGS. 5 and 6, in one embodiment, afirst portion 232 of the gap G extends from the bridge section 226towards the first end 210 of the load beam 206, and a second portion 234of the gap G extends between the second end 212 of the load beam 206 andthe bridge section 226. In other embodiments, additional bridge sectionsmay extend across the gap G, thus further dividing the gap Glongitudinally.

The bridge section 226 may also be substantially centered longitudinallyalong the gap G. Thus, a length of the first portion 232 of the gap Galong the longitudinal axis L may be substantially equal to a length ofthe second portion 234 of the gap G along the longitudinal axis L. Inother embodiments, the bridge section 226 may be off-center along thelongitudinal axis L. For example, if the bridge section 226 is shiftedtowards the first end 210, the base region 214 may have a lower resonantfrequency, and the constraint layer 208 affixed thereto may have anincreased damping effect. Thus, the bridge section 226 may be movedfarther away from or closer to the first end 210 in order to “tune” aresonant frequency and damping effect.

The bridge section 226 can have any of a variety of lengths measuredalong the longitudinal axis L. In one embodiment, a ratio of a length ofthe bridge section 226, illustrated as BL in FIG. 6, measured along thelongitudinal axis L of the load beam 206 to a length of the base region214, illustrated as TL in FIG. 6, measured along the longitudinal axis Lof the load beam 206 may be between 1/5 and 1/3. In one embodiment, thefirst portion 232 of the gap G and the second portion 234 of the gap Gmay therefore each have a length of approximately 1/3 to 2/5 the lengthTL of the base region 214. In some embodiments, the length TL of thebase region 214 may be between approximately 0.5 mm and 2 mm, andtherefore the length BL of the bridge section 226 may be betweenapproximately 0.1 mm and 0.66 mm.

The load beam 206 may further include a first leg section 236 extendingfrom the first lateral section 222 towards the first end 210 of the loadbeam 206, and a second leg section 238 extending from the second lateralsection 224 towards the first end 210 of the load beam 206. These legsections 236, 238 may be monolithic with the lateral sections 222, 224and may also be separated at least in part by a lightening feature. Asillustrated, this lightening feature may be formed by the removal of atleast some of the material of the load beam, thereby separating the legsections 236, 238. The lightening feature may be substantially widerthan the gap G separating the first and second lateral sections 222,224. For example, as illustrated in FIG. 6, a width RW of the lighteningfeature may be between approximately 0.4 mm and 1.0 mm. In oneembodiment, the width RW of the lightening feature may be at least twicethe width GW of the gap G. Of course, other geometric relationships arepossible in other embodiments.

In the illustrated embodiment, the base region 214 is flared laterallyin a direction of the second end 212 of the load beam 206 from the firstand the second leg sections 236, 238. Of course, in other embodiments,the base region 214 may have a different geometry. For example, in oneembodiment, the base region 214 may have substantially the same widthalong the longitudinal axis L. In other embodiments, more complexgeometries may be employed to form the base region 214.

FIG. 7 shows a side view of the load beam 206. As illustrated, the firstend 210 may be bent out of plane from the rest of the load beam 206. Ofcourse, in other embodiments, more or less complex geometries may bechosen for the load beam 206.

In one embodiment, as illustrated in FIG. 8, the constraint layer 208may have a shape that is substantially congruent with the shape of thebase region 214. Thus, the constraint layer 208 may overlay both thefirst lateral section 222 and the second lateral section 224 and extendacross the gap G. As described above, in operation, the constraint layer208 may act to damp vibrations that arise in the base region 214. Inother embodiments, different geometries may be used for the constraintlayer 208.

Returning to FIG. 4, the adhesive layers 220 a, b (collectively 220) maycouple the constraint layer 208 to the base region 214 of the load beam206. In one embodiment, the suspension 200 comprises a first adhesivelayer 220 a between the first lateral section 222 and the constraintlayer 208, and a second adhesive layer 220 b between the second lateralsection 224 and the constraint layer 208. The first adhesive layer 220 amay be separate from the second adhesive layer 220 b. Thus, in oneembodiment, the adhesive layers 220 may couple the constraint layer 208to the base region 214 without overlaying any portion of the gap G,thereby minimizing adhesive exposure within the disk drive.

In other embodiments, a single adhesive layer may couple the constraintlayer 208 to the load beam 206. For example, an adhesive layer having ashape generally similar to the base region 214 may be used, and such anadhesive layer may even include a bridge section shaped similarly to thebridge section 226. In other embodiments, more than two adhesive layersmay couple the constraint layer 208 to the load beam 206.

Any of a variety of adhesive materials may be used to form the adhesivelayers 220. In one embodiment, the adhesive layers 220 act in concertwith the constraint layer 208 to provide damping, and thus materials maybe chosen for the adhesive layers 220 to enhance this damping effect. Inone embodiment, a viscoelastic adhesive may be used for the adhesivelayers 220. For example, JDC MP65 or JDC MD15 adhesives, both producedby JDC, Inc., may be used. In another embodiment, 3M 242 adhesives,produced by 3M, may be used. In still other embodiments, other adhesivematerials may be used.

The adhesive layers 220 may have any of a variety of thicknesses. In oneembodiment, the adhesive layers 220 may have a thickness of betweenapproximately 1 mil and 8 mil (i.e., between approximately 0.025 mm and0.2 mm). Of course, depending on the adhesives chosen, differentthicknesses may be optimal.

In still other embodiments, the adhesive layers 220 may be omitted. Forexample, the constraint layer 208 may itself comprise an adhesive layeror may otherwise have adhesive properties and may be coupled to the baseregion 214 without additional adhesives. In other embodiments, theconstraint layer 208 may be otherwise coupled to the base region 214.

FIG. 9 illustrates a flow chart for a method 900 of manufacturing asuspension for a disk drive, according to one illustrated embodiment.This method 900 will be discussed in the context of the disk drivesuspension 200 of FIGS. 2-8. However, the acts disclosed herein may beexecuted to manufacture a variety of different disk drive suspensions,in accordance with the described method.

As described herein, all of the acts comprising the method 900 may beorchestrated in one embodiment by a processor according to an automaticsuspension manufacturing algorithm, based at least in part oncomputer-readable instructions stored in computer-readable memory andexecutable by the processor. Of course, a manual implementation of oneor more acts of the method 900 may also be employed.

At act 902, a load beam 206 is formed, the load beam 206 having a firstend 210 and a second end 212 and having a longitudinal axis L betweenthe first end 210 and the second end 212. The load beam 206 may beformed in a variety of ways. In one embodiment, the load beam 206 isformed via an etching, stamping or casting process. In anotherembodiment, the load beam 206 may be formed via other machiningprocesses.

At act 904, a bridge section 226 is formed, the bridge section 226extending across a gap G in a base region 214 of the load beam 206proximate the second end 212, the gap G extending between a firstlateral section 222 of the load beam 206 and a second lateral section224 of the load beam 206. The bridge section 226 and the correspondinggap G may be formed in a variety of ways. In one embodiment, acts 902and 904 may be performed substantially simultaneously using the samemanufacturing process. However, in other embodiments, acts 902 and 904may be performed at different times using different manufacturingprocesses. For example, in one embodiment, a general shape of the loadbeam 206 may be formed by a stamping or casting process at act 902, andthen the bridge section 226 may be formed via a machining process at act904.

At act 906, a constraint layer 208 is overlaid across at least a portionof the base region 214. In one embodiment, the constraint layer 208 maybe aligned with at least a portion of the base region 214 and coupledthereto. For example, a first adhesive layer 220 a may be formed betweenthe first lateral section 222 and the constraint layer 208, and a secondadhesive layer 220 b may be formed between the second lateral section224 and the constraint layer 208. In other embodiments, other methodsand/or structures for coupling the constraint layer 208 to the baseregion 214 may be employed.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, schematics,and examples. Insofar as such block diagrams, schematics, and examplescontain one or more functions and/or operations, each function and/oroperation within such block diagrams, flowcharts, or examples can beimplemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof. Inone embodiment, the present subject matter may be implemented viaApplication Specific Integrated Circuits (ASICs). However, theembodiments disclosed herein, in whole or in part, can be equivalentlyimplemented in integrated circuits, as one or more programs executed byone or more processors, as one or more programs executed by one or morecontrollers (e.g., microcontrollers), as firmware, or as any suitablecombination thereof.

We claim:
 1. A method of manufacturing a suspension for a disk drivecomprising: providing and assembling an actuator coupling plate, a bendregion, a load beam, and a head receiving gimbal; wherein the load beamhas a first end adjacent the head receiving gimbal, and the load beamhas a base region with a second end adjacent to the bend region, thebend region being disposed between the second end and the actuatorcoupling plate, the load beam having a longitudinal axis bisecting thefirst end and bisecting the second end, the load beam including firstand second legs, and a lightening opening disposed between the first andsecond legs; wherein the base region of the load beam includes a gapthat is closer to the second end than is the lightening opening, alateral width of the lightening opening being at least twice a lateralwidth of the gap, the gap and the longitudinal axis being disposedbetween a first lateral section of the base region and a second lateralsection of the base region; wherein the base region of the load beamincludes a bridge extending laterally across the gap; and overlaying aconstraint layer laterally across the gap and over the bridge.
 2. Themethod of claim 1, further comprising: forming a first adhesive layerbetween the first lateral section and the constraint layer; and forminga second adhesive layer between the second lateral section and theconstraint layer.
 3. The method of claim 2, wherein each of the firstand second adhesive layers comprises a viscoelastic adhesive and has anadhesive thickness in the range of 0.025 mm to 0.2 mm.
 4. The method ofclaim 1, wherein the gap is substantially aligned with the longitudinalaxis of the load beam.
 5. The method of claim 1, wherein a first portionof the gap is disposed on one side of the bridge, and a second portionof the gap is disposed on another side of the bridge, the first portionextending from the bridge towards the first end of the load beam, andthe second portion extending between the second end of the load beam andthe bridge.
 6. The method of claim 1, wherein the first leg extends fromthe first lateral section towards the first end of the load beam, andthe second leg extends from the second lateral section towards the firstend of the load beam.
 7. The method of claim 1, wherein overlaying theconstraint layer comprises overlaying the constraint layer acrosssubstantially all of the base region.
 8. The method of claim 7, whereinthe constraint layer is substantially congruent with the base region. 9.The method of claim 1, wherein a ratio of a length of the bridgemeasured along the longitudinal axis of the load beam to a length of thefirst lateral section measured along the longitudinal axis of the loadbeam is between 1/5 and 1/3.
 10. The method of claim 9, wherein thelength of the bridge measured along the longitudinal axis of the loadbeam is in the range of 0.1 mm to 0.66 mm.
 11. The method of claim 1,wherein the actuator coupling plate is a swage plate.
 12. The method ofclaim 1, wherein the constraint layer has a thickness of between 0.025mm and 0.15 mm.
 13. The method of claim 1, wherein the lateral width ofthe gap is in the range of 0.05 mm to 0.4 mm.
 14. The method of claim 1,wherein the lateral width of the lightening opening is in the range of0.4 mm to 1.0 mm.
 15. The method of claim 1, wherein the load beamcomprises stainless steel, and providing the load beam includes etchingthe gap in the load beam.